In the winter season in northern climes pneumatic tires used on vehicles throw snow, ice mixed with salt and debris onto the undersurfaces of the fenders or mud-guards where it collects and builds up to the extent of impeding mobility and steering of the vehicle. Moreover, the accumulated mixture containing salt and moisture rapidly corrodes and deteriorates the metal of the fenders and adjacent chassis parts. If the vehicle is parked outdoors, most of the accumulation stays on the metal and continues its corroding action as the weather moderates sufficiently to thaw the mixture, and by that time a surface coating of the corroding mixture is caked on the surface and does not drop off even though thawed.